摘要
为了探究不同裂隙倾角、连通率对混凝土力学行为及微观损伤特性的影响,采用岩石力学及声发射配套系统,对17组相同配合比、不同裂隙倾角和连通率的混凝土进行了单轴压缩及声发射监测试验。研究结果表明:混凝土的强度、变形破坏及内部损伤等与裂隙倾角和连通率密切相关,且均表现出各向异性的特征。相同倾角下,连通率越大,混凝土的延性和峰值当量强度越低,连通率一定时,延性和峰值当量强度呈先减后增的整体趋势;无裂隙时,声发射主要集中于峰值应力前后,表现为脆性破坏特征,大/小倾角及小连通率时,声发射表现为脆延性破坏形式,大/小倾角及大连通率时,声发射信号主要表现为"S"型的3阶段延性特征,主要集中于屈服至峰值应力阶段。基于声发射损伤模型计算得到的损伤演化过程表明:模型计算结果和试验结果吻合良好,且混凝土内部的损伤演化随着倾角和连通率的变化而表现各异,连通率越大时,损伤发展越平缓,越充分。
For the purpose of studying the impact of different fissure angles and continuity on the mechanical behavior of concrete and the microscopic damage characteristics, the rock mechanics and the supporting system of acoustic emission are adopted to conduct the uniaxial compression and acoustic emission monitoring test to 17 groups of concretes with the same mixing proportion and different fissure angles and continuities. The research result indicates that: The strength, deformation fracture and internal damage of concrete are closely related to the fissure angle and continuity, and show the anisotropic characteristics. Under the same inclination angle, the larger the continuity is, the lower the concrete ductility and peak yield strength are. The concrete ductility and peak yield strength tend to decrease at first, then increase later as a whole upon certain connectivity rate. Acoustic emission mainly concentrates on the peak stress when there is no crack, which appears as characteristics of brittle failure. The acoustic emission shows the brittle ductile failure mode in case of the large/small dip angle and small continuity, while the acoustic emission signal mainly shows "S"-shaped ductile characteristics at three stages in case of the large/small dip angle and large continuity, which mainly focuses on the stress stage from yield to peak value. The damage evolution process based on the damage model for acoustic emission indicates that the calculation results of model coincide with the test results well, and the internal damage evolution of concrete behaves differently with the change of angle and continuity. The larger the continuity is, more gentle and more sufficient the damage development is.
作者
贾平虎
Jia Pinghu(Guangdong Xiangfei Highway Engineering Supervision Co.,Ltd.,Guangzhou 510000,China)
出处
《甘肃科学学报》
2019年第2期81-86,共6页
Journal of Gansu Sciences
关键词
混凝土
裂隙
倾角
连通率
声发射
损伤
Concrete
Fissure
Inclination angle
Connectivity rate
Acoustic emission
Damage
